Over the past 50 years, developments in electronic and optical technologies have meant that it has become possible to perform many operations laparoscopically. The unique feature distinguishing laparoscopic from open abdominal or vaginal surgery is the need to insert needles, trocars and cannulas for initial entry into the abdomen, the insertion of the primary trocar being made blindly in most cases. This may result in inadvertent bowel or vascular injury which can be responsible for major morbidity and mortality. In the last 25 years great efforts have been made for the prevention of these injuries by developing so called safe entry techniques especially because almost 75% of the complications of laparoscopic surgery occur at the time of primary entry site into the abdomen, before even surgery has begun.
The classic site for gaining access into the abdominal cavity by insertion of the first trocar is the umbilicus, this being the thinnest part of the abdominal wall, with abdominal fasciae fused into the umbilical ring.
The problem resides in the proximity of the large retroperitoneal vessels and the frequency of infraumbilical adhesions by the bowel and omentum found in almost 10% of cases, which can lead to injury of the aforementioned structures, especially in the case of a previous laparotomy or obese or too thin patients.
The closed entry technique comprises the Veress needle technique and the direct entry technique. The technique used by most gynecologic surgeons implies inserting a hollow needle called the Veress needle into the abdomen through the abdominal wall, after lifting the latter, performing a series of tests that whiteness the probable location of the tip inside the abdomen, insufflation of the abdomen with CO2 to a predetermined set pressure and insertion of a trocar cannula after the removal of the needle. Note that there are three blind steps in performing this procedure: insertion of the Veress needle, insufflation and insertion of the cannula. The direct trocar entry implies insertion of the primary trocar through the umbilicus, followed by insertion of the optics and the insufflation of the abdominal cavity. Although it takes less time to perform than the Veress needle technique, and is associated with less minor insufflation-related side effects, the possible complications associated with insertion of a large sharp instrument blindly could prove to be severe.
The open Hasson technique (U.S. Pat. No. 3,817,251) implies the visualization and cutting of the abdominal layers upon entry by using blunt and sharp dissection, and insertion of the primary trocar under sight. This technique has not lowered the rate of bowel complications however in large population studies, just the recognition of them.
The radially expanding access system (U.S. Pat. No. 5,827,319), was developed to minimize tissue trauma. This system uses a pneumoperitoneum needle with a polymeric sleeve. Following routine insufflation the needle is removed leaving the outer sleeve in situ, followed by direct dilatation of the sleeve into creation of a port. Complications are similar to the ones of the closed technique.
Visual trocars imply the use of optics through the cannulas upon insertion through the abdominal layers (U.S. Pat. No. 6,638,265, States Surgical Corps Visiport™ trocar and the Ethicon Endosurgery's Optiview™). Studies have not shown a reduction of entry complication by using these techniques, but only the rate of recognition.
However, the incidence of first entry complications remains the same in the last 25 years, whichever technique is performed, in spite of the technical progress, studies not showing the superiority of either technique into lowering the complication rate.
Attempts to use ultrasound as a recognition tool for umbilical adhesions have been made. The “Visceral slide” technique developed by F. Tu et al. uses an abdominal probe placed over the umbilicus and the patient is asked to take very quick and large breaths. The underlying viscera (bowel) move freely relative to the abdominal wall for 3-5 in normal cases. In the event of underlying adhesions, there is no or little movement.
The PUGSI technique (Peroperative periumbilical ultrasound-guided saline infusion) developed by C. Nezhat et al. implies performing visceral slide followed by infraumbilical injection of 6-10 cc of sterile saline through a spinal needle under direct ultrasound guidance. Formation of fluid pocket and non-dispersion suggest subumbilical adhesions.
U.S. Pat. No. 5,209,721 uses a Veress needle with an ultrasonic wave generator and a sensor mounted thereon, monitoring ultrasonic pressure waves reflected from internal organs or tissues located along the insertion path of the needle.
Various designs of percutaneous needle guides for attachment to non-invasive medical scanning devices, for example hand-held transducer probes, are known in the art. These guides may be used to direct a percutaneous needle to a needle entry site, which is located alongside the scanning device on an epidermis of a scanned body, and which corresponds to a subcutaneous target located by the device.